Dual-passband filter using dual-mode substrate-integrated waveguide resonator

ABSTRACT

A novel dual-band bandpass filter (DB-BPF) based on SIW dual-mode resonant cavity is proposed in this study. This resonant cavity works in the degenerate mode TE₁₀₂ mode and TE₂₀₁ mode. The two modes of operation are coupled by opening a window between the resonant cavities, and the passband frequency of the DB-BPF is adjusted by controlling two degenerate modes. This filter works at 9 GHz and 9.5 GHz and has a 3-dB fractional bandwidth of 2.2% and 3.5% GHz, respectively, and has three transmission zeros (TZs) which improve out-of-band rejection and isolation between high-passband and low-passband. The return loss in the high-passband and low-passband is below 13 dB; the insertion loss of the high-passband and low-passband is 2.32 dB and 3.16 dB, respectively. The measured results agree well with the simulation results, which proves the feasibility of the design method.

KEYWORDS:

• Degenerate mode
• dual-band bandpass filter
• dual-mode resonator
• SIW

Acknowledgments

The work was supported in part by the National Natural Science Foundation of China (Grant No: 62171097) and by the National Defense Basic Scientific Research program of China (Grant No: JCKYS2021DC07).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The work was supported by the National Defense Basic Scientific Research Program of China [JCKYS2021DC07]; National Natural Science Foundation of China [62171097].